In .-\I. the problem of selecting (high-level) actions in dynamic and not completely pre-dictable environments translates into the problem of designing controllers that can mapsequence of observations into actions so that certain goals are achieved.One approach to high-level controllers is high-16 v t i pr-ogmrn r n irrg. Basically. we imag-irw a sj.stt3rn executing a iiigii-level prograrrl with respect to a background theory ofaction. Khereas the background t h e o.